Add Elo rating system with match entry and CSV upload

- Implement EloCalculator service for 2v2 Euchre matches
- Create background job processing with GoodJob
- Add single match entry form
- Add CSV upload for batch match entry
- Create player rankings view
- Add database schema for matches and elo snapshots

app/jobs/calculate_elo_job.rb

@@ -0,0 +1,86 @@
+# frozen_string_literal: true
+
+module EuchreCamp
+  module Jobs
+    class CalculateEloJob
+      def self.perform_later(match_id)
+        # Enqueue job using GoodJob's database directly
+        rom = EuchreCamp::App["persistence.rom"]
+        
+        job_params = {
+          queue_name: "default",
+          priority: 0,
+          serialized_params: { "match_id" => match_id }.to_json,
+          scheduled_at: Time.now,
+          created_at: Time.now,
+          updated_at: Time.now,
+          job_class: "EuchreCamp::Jobs::CalculateEloJob",
+          executions_count: 0
+        }
+        
+        rom.relations[:good_jobs].insert(job_params)
+      end
+
+      def self.perform(match_id)
+        # This is the actual job execution
+        match = find_match(match_id)
+        return unless match
+
+        # Get current player ratings
+        player_ratings = fetch_player_ratings(match)
+
+        # Calculate new ratings
+        calculation_results = EuchreCamp::Services::EloCalculator.calculate(
+          player_ratings: player_ratings,
+          team_1_players: [match[:team_1_p1_id], match[:team_1_p2_id]],
+          team_2_players: [match[:team_2_p1_id], match[:team_2_p2_id]],
+          team_1_score: match[:team_1_score],
+          team_2_score: match[:team_2_score]
+        )
+
+        # Update player ratings and create snapshots
+        update_player_ratings(calculation_results, match_id)
+      end
+
+      private
+
+      def self.find_match(match_id)
+        rom = EuchreCamp::App["persistence.rom"]
+        rom.relations[:matches].by_pk(match_id).one
+      end
+
+      def self.fetch_player_ratings(match)
+        rom = EuchreCamp::App["persistence.rom"]
+        player_ids = [
+          match[:team_1_p1_id],
+          match[:team_1_p2_id],
+          match[:team_2_p1_id],
+          match[:team_2_p2_id]
+        ]
+
+        players = rom.relations[:players].where(id: player_ids).to_a
+        players.each_with_object({}) do |player, hash|
+          hash[player[:id]] = player[:current_elo] || 1000
+        end
+      end
+
+      def self.update_player_ratings(results, match_id)
+        rom = EuchreCamp::App["persistence.rom"]
+
+        results.each do |player_id, data|
+          # Update player's current Elo
+          rom.relations[:players].where(id: player_id).update(current_elo: data[:rating_after])
+
+          # Create Elo snapshot record
+          rom.relations[:elo_snapshots].insert(
+            player_id: player_id,
+            match_id: match_id,
+            rating_before: data[:rating_before],
+            rating_after: data[:rating_after],
+            rating_change: data[:rating_change]
+          )
+        end
+      end
+    end
+  end
+end